firstly, the issue of contango and carry could open a can of worms here.
Secondly, if a market is in steep backwardation it implies that the physical is very scarce. For instance, if there was a squeeze in live cattle how would you intend to borrow non-existent cattle? Insemination, gestation, maturation mean that natural methods will not deliver cattle to you soon enough. And no one will enter into any kind of synthetic cattle swap because they won't be able to hedge with the physical either.
This more or less extends to all commodities - and explains backwardation. At some point the premium (say in chicago cattle) may becomes so large that it becomes economic to take australian or french cows, put them on an airbus, and deliver them into the short chicago market.